CVE-2024-23185 Affecting dovecot package, versions <1:2.3.21+dfsg1-2ubuntu6


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.49% (65th percentile)

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  • Snyk IDSNYK-UBUNTU2404-DOVECOT-7830400
  • published2 Sept 2024
  • disclosed10 Sept 2024

Introduced: 2 Sep 2024

CVE-2024-23185  (opens in a new tab)

How to fix?

Upgrade Ubuntu:24.04 dovecot to version 1:2.3.21+dfsg1-2ubuntu6 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream dovecot package and not the dovecot package as distributed by Ubuntu. See How to fix? for Ubuntu:24.04 relevant fixed versions and status.

Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up "full_value" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usage. It doesn't matter whether it's a single long header line, or a single header split into multiple lines. This bug exists in all Dovecot versions. Incoming mails typically have some size limits set by MTA, so even largest possible header size may still fit into Dovecot's vsz_limit. So attackers probably can't DoS a victim user this way. A user could APPEND larger mails though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in general). One can implement restrictions on headers on MTA component preceding Dovecot. No publicly available exploits are known.

CVSS Base Scores

version 3.1